Method of assembling textile fibers hydraulically



Jan. 11, 1955 E L-E 2,698,972

METHOD OF ASSEMBLING TEXTILE FIBERS HYDRAULICALLY Filgd 1mg. 19, 1952 United States Patent METHOD OF ASSEMBLING TEXTILE FIBERS HYDRAULICALLY This invention pertains to a method of assembling fibers of textile length in approximately parallel relation to form a strand or roving suitable for use in spinning, and relates more especially to a novel method of preparing textile roving in a continuous process and at aspeed of production which may greatly exceed that of prior procedures, and in which use is made of certain principles of hydraulics for assembling the fibers in parallel relation.

In the preparation of spun yarn from fibers of textile length (i. e. fibers measuring at least of an inch) the principal object sought is to dispose the fibers in as nearly parallel relation as is possible, and, if the fibers be of different types or lengths, the distribution of these various kinds of fibers as uniformly in the strand as is practicable. These operations, preliminary to spinning, are customarily performed mechanically, making use of costly and complicated machinery. In accordance with prior practice, the repeated contact of the fibers with machine parts which flex the fiber, stretch it and abrade it, results in much weakening and breakage of the fiber with resultant waste. All of these manipulations contribute very substantially to the cost of production of spun yarn.

The present invention has for its principal object the provision of a novel method, whereby the cost of preparing roving suitable for spinning is greatly reduced as compared with previous commercial processes; to provide a process of preparing roving such that the fiber is subject to a minimum number of flexings or contacts with mechanical parts, thus reducing weakening or breakage of the fiber to a minimum; to provide a method of preparing textile roving which lends itself to the comingling of fibers of different types and lengths in a definite percentage ratio and in uniform distribution; and to provide a method wherein certain principles of hydraulics are effectively employed in such a way as to place the fibers in substantially parallel assembly to form a roving while the fibers are freely suspended in a fluid stream moving at a velocity which substantially exceeds the linear velocity of production of roving by usual prior methods of procedure. Other and further objects and advantages will be pointed out in the following more detailed description and by reference to the accompanying drawings wherein Fig. l is a fragmentary diagrammatic elevation, illustrative of apparatus such as may be used in the practice of the improved method;

Fig. 2 is a fragmentary plan view of the apparatus shown in Fig. 1; and

Fig. 3 is a diagrammatic horizontal section through the axis of a pipe in which flows a stream of water, and wherein the velocity gradient between the walls of the pipe and axis of the flowing stream and the consequent action on suspended fibers is diagrammatically indicated.

In the preparation of paper or paper-like materials, comprising very short fibers felted together, it is the common practice to suspend the short fibers in water and to discharge the suspension onto a moving screen on which the fibers are laid down to form a matted film, but the fibers which are used in such processes are usually of very short length, much less than the lengths of fibers used for textile purposes, and in paper making, one of the principal objects sought is to prevent, so far as possible, the parallel arrangement of the fibers as they are laid down onto the screen. In paper making the velocity of the flow of the water suspension of pulp fiber is low.

In low velocity streams, the velocity gradients are much less pronounced than in streams of high velocity, and thus in streams flowing at low velocity there are no forces present sufiicient to have any appreciable effect upon the orientation of the fibers. Thus fibers delivered in such a stream in disorderly arrangement do not tend to place themselves parallel with each other, nor to migrate toward the axis of the stream. Thus, in the paper industry, it has been observed that when water carrying pulp fiber in suspension is conveyed through long pipes, particularly pipes of small diameter, difiiculty is experienced because of the tendency of the pulp fiber to come to rest against the Wall of the pipe with eventual plugging of the pipe.

It has previously been proposed to prepare textile roving by suspending the fiber in water and delivering the suspension onto a wire mesh screen arranged in a tank of water with provision for oscillation of the screen transversely in the expectation that the fibers would arrange themselves in parallel relation and form a sliver or roving extending along the center line of the screen; however, so far as is known, such procedure has never proven practical or been adopted commercially.

Studies of the behavior of pulp fiber suspended in a stream of water of low velocity (see the article by Moss and Bryant published in the Technical Association Papers of the Pulp and Paper Industry 1938) seem to indicate that pulp fibers, suspended in a smoothly flowing stream of low velocity such as is common in paper making, show no tendency to align themselves parallel to the axis of the stream and that only at points where turbulence exists (for example, where the stream is suddenly constricted or where the stream suddenly changes direction) is there anlz tendency of fibers to become parallel with each 0t er.

However, experiment with discrete fibers of textile length, freely suspended in water moving at a relatively high velocit for example, eight feet per second, in a pipe whose inner surface is very smooth, even if the pipe be of small diameter, for example /8 of an inch, show a very strong tendency to migrate toward and to align themselves with the axis of the pipe, whether the pipe be straight or bent.

When a fluid flows through a smooth, straight pipe of small diameter at a rate (measured in terms of quantity discharged) 0f the order of from two to ten feet per second, the actual velocities of individual particles of this fluid, located at ditferent distances respectively from the axis of the pipe at any given transverse section, are not the same. Those particles of the fluid which contact the wall of the pipe have zero velocity (in theory, at least) while those at the axis of the pipe have maximum velocity. In other words velocity gradients are present in the smoothly flowing fluid, and these velocity gradients have the same or similar effect in causing suspended fibers to migrate toward and arrange themselves parallel to the axis of the pipe as does a sudden change in velocity or direction in a slow-moving stream.

In accordance with the present invention, this phe nomenon is used for disposing fibers of textile length in close assemblage and in parallel relation, and, if the fibers to be so assembled be of different type or length, to distribute them substantially uniformly throughout such assemblage.

As one example whereby the above objects may be obtained, the fibers which are to form the desired roving, for instance cut rayon fibers of an average length of 1 /2 inches, are dispersed in a suitable fluid medium, usually water, and by agitation or otherwise are separated to provide, nearly as is practicable, a uniform distrib ut1on of separated or discrete fibers per cubic umt of liquid. From this suspension, liquid, with its suspended fibers, is allowed to flow by gravity through a smooth pipe preferably of small diameter, for instance of an inch, and under a pressure head, such as to produce a velocity of discharge of from two to ten feet per second. The fluid delivered from this pipe is received on a moving endless belt of wire mesh or similar material, whose fiber receiving run moves at a linear velocity substantlally equaling that of the fluid in the pipe at the instant before it emerges from the pipe. As the fluid leaves the pipe, the fibers, which before reaching the point of discharge, have arranged themselves in parallel relation close to the axis "ice of the pipe, are delivered onto the moving belt without substantial disturbance of their relative arrangement, and are drawn off by the moving belt in the form of a ribbonlike band which, at the terminus of the fiber supporting run of the belt, may be lifted off of the belt as a continuous sliver or roving (devoid of twist) and whose constituent fibers are substantially parallel and in close contact. Such sliver or roving may then be given a preliminary twist to make it self-sustaining, if desired, and is then wound to form a package for delivery to the spinning frame.

Referring to the drawings which show a simple arrangement of parts suggested for use in the practice of the method, but without intent to suggest that other apparatus may not be useful for the purpose, the numeral 1 designates an endless belt of wire mesh or the like, such for example as is used in a paper-making machine, this belt being carried by suitable rolls 2 and 3, one of which may be driven so as to advance the upper or fiber receiving run 1a of the belt in the direction of the arrow 4-. As illustrated, this upper run of the belt is substantially horizontal, although it is contemplated that this run of the belt may be inclined, if desired,

The numerals 5 and 6 designate suitable reservoirs or fluid containers of any suitable shape and capacity appropriate to hold a body W of liquid, for example water, in which fibers F or F, of textile length are suspended. As here illustrated, there are two of the containers or reservoirs with the suggestion that the fibers F in one container may differ in some respect, for example in nature or in length, from the fibers F in the other container. It is further to be understood that if, for example fibers of a greater number of kinds are to be incorporated in the desired roving, the number of containers may be correspondingly increased. On the other hand, a single container may be employed, particularly where the fibers to be formed onto the roving are substantially of the same kind or character. Likewise, it several containers are available they may all receive fibers of the same kind and character if desired. For example, if it be desired to form a roving having a great number of fibers at any given transverse section, the desired result may be obtained by employing a large number of containers, all supplied with fibers of the same kind suspended in water therein, and each having a discharge pipe of relatively small diameter, instead of using a single, large receptacle or reservoir with a delivery pipe of a size to goiitduct a great number of fibers simultaneously to the Whatever the arrangement of container or reservoir, it is provided with a delivery pipe such as the pipes 7 and 8 respectively, leading from the lower part of the container. Preferably such pipe comprises a substantially vertical upper portion, preferably straight, these pipes being of some material which provides a very smooth interiorsurface, for example, glass or a porcelain-lined metal pipe. Optimum results have heretofore been ob- I tained by the use of pipe approximately /s inch in internal diameter. When several pipes such as the pipes 7 and 8 are provided for leading the liquid from the corresponding number of reservoirs, it is desirable to merge these pipes into a single delivery pipe, such as the pipe 9, rather than to have each of these several pipes 7, 8 or the like, discharge independently onto the surface of the belt 1. Thus, as here illustrated, the pipes 7 and 8 rnerge smoothly with the pipe 9, whose delivery end 10 is directly above and desirably very close to the upper surface of the run 1a of the belt. It is very desirable that n merging the pipes 7 and 8 with the pipe 9, the unction of the several pipes present a very smooth inner surface, devoid of any roughness or projections, such as might cause irregular turbulence in the flowing fluid and thereby disarrange the fibers.

Referring to Fig. 3, which is a diagrammatic horizontal section to large scale, through a pipe P in which flows a body of liquid in the direction of the arrow Z, it is a recognized principle of hydraulics that the velocity of the flowing liquid, due to viscosity and other factors, is substantially zero at the point of contact of the liquid with the inner surface of the pipe, while the maximum velocity of the flowing fluid is in the axis XX of the pipe. Thus. the liquid may be considered to be made up of an infinite number of filaments each shaped (in horizontal section) somewhat as indicated at T1, T2, T3, etc., wherein the velocity at the base of the filament (indicated at V0) is substantially zero, while the velocity at the axis'of' the pipeas'indicated at Vmis a maximum;

On this assumption, and assuming a fluid velocity of an average value (throughout any cross-section of the pipe) to be at least 2 feet per second, and supposing that discrete fibers of textile length, indicated at P enter the pipe at its left hand end as viewed in Fig. 3, in indiscriminately oriented relation in free suspension in the liquid, the individual fibers, as they are moved forward by the flowing fluid, are dragged along by the latter, that end of any fiber which lies nearest to the axis of the pipe tending to be dragged along with increasing velocity, thus causing the fiber to move bodily toward the axis of the pipe and to trail out and become straight, so that eventually the fibers will be found to be traveling along in substantially parallel relation close to the axis of the pipe as indicated at P Fig. 3.

Referring to Fig. l, and assuming that the fibers F and F from the reservoirs 5 and 6 enter the upper portions of the pipes 7 and 8 in a disorderly manner, with no definite orientation as indicated in F the flow of the liquid at a velocity of two or more feet per second downwardly through the pipes 7 and S will result in the straightening of the fibers and their parallel arrangement near the axis of the pipe as indicated in F Since the streams in the pipes 7 and 8 merge smoothly and without turbulence as they enter the pipe 9, the fibers carried by these two streams mingle within the pipe 9 in the exact proportions in which they are delivered into the pipe 9 by the pipes 7 and 8 respectively and take up a position at the axis of the pipe 9 without substantial disturbance of their parallel relation. They are then all discharged into the upper run 1a of the belt to form a narrow ribbon R, Fig. 1. Since the upper run 1a of the belt is advanced at a linear speed substantially equal to the velocity of discharge of liquid onto the belt, this ribbon is unbroken and continuous. At the delivery end of the belt, this ribbon R may be taken from the belt, for example, by passing it between rolls 11 and 12 and then in any suitable way, for example by guide rolls 13 and 14 it may be delivered to a spindle 15 which winds the ribbon with any desired amount of twist to form a package K.

As above noted, the proportion of the fibers F and P which make up the ribbon R will depend entirely upon the rate at which the fibers of these two kinds are delivered by the pipes 7 and 8. This relative rate may. be determined in various ways, for example by varying the concentration of the fibers in the liquid contained in the respective reservoirs, or by means which controls the relative quantities of liquid discharged per unit of time. Thus by providing a definite predetermined ratio between the number of fibers passing down through the pipes 7 and 8 respectively per unit of time, this ratio will be preserved in the ribbon R, and because the fibers from the two pipes intermingle, while in fluid suspension in the pipe 9, this relation between the two kinds of fiber will be uniform throughout the length and width of the ribbon R. Thus, the most perfect of mixing and uniformity of product is obtainable by this method of procedure.

As here illustrated, the pipe 9 is of approximately the same diameter as the pipes 7 or 8. Such an arrangement tends to increase the velocity of the fluid in the pipe 9 as compared with that in the pipes 7 or 8, and such increase may be usefully employed to insure the realignment of fibers which may have been slightly disturbed at the point of union of streams from the pipes 7 and 8. However, it is not necessary that such increase in velocity take place, and if desired the pipe 9 may be of a iameter large enough to provide the same velocity of fluid through the pipe 9 as exists in the pipes 7 and 8.

While one simple form of apparatus and sequence of steps has herein been described and illustrated, it is to be understood that the invention is broadly inclusive of any and all modifications, both of apparatus and of method steps which fall within the scope of the appended claims.

I claim:

1. That method of assembling fiber of textile length to form a roving for use in spinning, said method comprising as steps dispersing the fibers substantially uniformly in a body of liquid in such quantity as to provide a substantially predetermined number of fibers per cubic unit of the liquid, drawing off liquid with its suspended fibers through an elongate passage of circular transverse section and having a smooth imperforate Wall at a discharge velocity of at least two feet per second, thereby causing the fibers to migrate toward the axis of the passage and to become straight and parallel to the axis of the passage, discharging the liquid as a stream from the end of the passage with the fiber disposed axially of the stream, and separating the liquid from the fiber without disturbing the relation established between the fibers while moving through the passage.

2. That method of assembling fibers of textile length to form a roving for use in making spun yarn, said method comprising as steps distributing the fiber substantially uniformly throughout a body of a liquid suspending medium, drawing off liquid with its suspended fibers from said body through an elongate passage of circular transverse section and under a pressure head such as to produce a uniform velocity of delivery of from two to ten feet per second whereby the suspended fibers within the passage migrate toward the axis of the passage and arrange themselves in substantially parallel relation, discharging the liquid with its parallelized fibers from the passage onto a support which allows the liquid to drain from the fibers, and moving the support away from the delivery end of the passage at a linear velocity substantially equal to the velocity of discharge of the liquid from the passage, thereby leaving the fibers in the form of an uninterrupted ribbon on the support.

3. That method of assembling fiber of textile length to form an untwisted sliver preparatory to spinning the fiber into yarn, said method comprisnig as steps establish ng a stream of liquid in an elongate passage having an unperforate wall at a discharge velocity of at least two feet per second, introducing the fiber to be assembled 1nto said passage whereby the velocity gradient, incident to fluid flow at said velocity, causes the fiber to migrate toward the axis of the stream and to become parallel to said axis, discharging the stream, with its axially disposed fibers, from the end of the passage, and separating the liquid and fiber without substantially disturbing the parallel arrangement of the fibers.

4. That method of assembling staple length rayon fiber to form a roving suitable for spinning and which contains the same predetermined number of fibers at each transverse section, said method comprising as steps suspending the fiber in a liquid medium, establishing streams of said fiber-carrying liquid in each of which the discharge velocity is at least two feet per second whereby in each of said streams the suspended fibers are caused to migrate toward the axis of the respective stream and to arrange themselves parallel to said axis, there being a sufiicient number of said streams so that the aggregate of fibers at the axes of the several streams equals the desired number of fibers in the roving to be made, then merging the several streams in such a way that the fibers located at the axes of the several streams commingle in the merged stream without substantially disturbing their parallel arrangement, and thereafter separating the liquid from the fibers without substantially disturbing the relative arrangement of the fibers.

5. Method of forming textile roving containing the same predetermined number of substantially parallel fibers at any selected transverse section, said method comprising as steps, establishing a plurality of flowing streams of water each in an elongate smooth-walled passage of the order of /8 of an inch in diameter, introducing into each of said streams discrete fibers of textile length, the aggregate of fibers introduced into the several streams being such as to provide the desired number of fibers per unit of cross section in the completed roving, maintaining a velocity of flow in each of said passages of at least 2 feet per second whereby the fibers in each stream are caused to migrate toward the axis of the stream and arrange themselves parallel to said axis, merging the several original streams to form a single combined stream wherein the velocity of flow is such as to cause the fibers supplied by the several original streams to assemble themselves in parallel relation at the axis of the combined stream, and thereafter separating the water from the fibers while continuing the advance motion of the fibers without substantial change in linear velocity, and imparting twist to the fibers suflicient to form a self-sustaining roving.

6. Method according to claim 5 wherein the fibers delivered into the several original streams are of different kinds and in proportion to the percentage of fibers of said different kinds which it is desired shall be combined in the roving to be made.

7. Method of forming textile roving which comprises as steps, establishing a flowing stream of water in an elongate, smooth-walled passage of the order of of an inch in diameter, introducing discrete fibers of textile length into said stream, maintaining a velocity of flow in the stream of at least 2 feet per second whereby the fibers are caused to migrate toward the axis of the stream and to arrange themselves parallel to said axis,

discharging the stream from said passage and separating the water from the fiber while continuing the advance motion of the fibers at substantially the same linear velocity which they had while suspended in the stream, thereby maintaining the relative arrangement of the fibers, and imparting twist to the fibers to make a self-sustaining rovlng.

8. Method of forming textile roving which comprises as steps, establishing a flowing stream of water in an elongate, smooth-walled passage of the order of of an inch in diameter, introducing discrete textile fibers of a selected average length into said stream, maintaining a uniform velocity of flow through said passage such that the velocity gradients thereby created are suflicient .to cause fibers of the particular selected length to migrate to the axis of the stream and arrange themselves substantially parallel to said axis, thereafter separating the water from the fibers while continuing the advance motion of the fibers without substantial change in linear velocity, thereby to avoid disturbance of the relative arrangement of the fibers, and imparting twist to the fibers.

9. Method of assembling fibers of textile length ac cording to claim 1 in which the liquid carrying the suspended fibers fills the passage and forms a cylindrical stream of uniform diameter.

References Cited in the file of this patent UNITED STATES PATENTS 1,532,083 Shaw Mar. 31, 1925 1,875,075 Mason Aug. 30, 1932 2,001,208 Minskey May 14, 1935 2,274,424 Miller Feb. 24, 1942 2,414,833 Osborne Jan. 28, 1947 

